Development of granular composites based on laponite and Zr/Fe-alginate for effective removal of uranium (VI) from sulfate solutions

Abstract

The object of research is granular composites based on zirconium-iron alginates and laponite. The task of research is to determine the influence of the Zr:Fe ratio on the structure of granular composites and efficiency of uranium (VI) removal from aqueous solutions. The influence of the zirconium and iron ratio on the parameters of the material's pore structure has been established, particularly on the change in the content of micropores within the matrix. The specific surface area of the materials ranges from 86 to 112 m²/g. The sorption properties of the composites regarding uranium (VI) have been investigated. The impact of the charge of surface groups and the form of uranium (VI) presence in sulfate solutions on their sorption characteristics has been demonstrated. The maximum adsorption capacity reaches 265.1 µmol/g at pH 6. It is shown that an elevated electrolyte content positively affects the efficiency of uranium (VI) removal in neutral and alkaline medium. It has been established that structural changes in the materials occur due to the intensive interaction of iron ions and alginate molecules, resulting in the formation of a dense gel-like structure. The mechanism of uranium (VI) removal is associated with the formation of surface complexes in the presence of electrolytes. The synthesized granulated composites exhibit improved removal efficiency of uranium (VI) under conditions of high mineralization of solutions, making them attractive for potential use as sorbents. The obtained results can be utilized in the development of effective methods for purifying water environments from uranium (VI) in high mineralization conditions, which is a relevant issue in the field of nuclear energy and the removal of radioactive substances from water systems